The present invention relates generally to communication interface adaptors and more specifically, to a housing for a single printed circuit board communication interface adaptor.
Communication interface adaptors of the prior art have generally included a plurality of circuits on individual printed circuit boards in a common housing with a power supply. The basic circuit boards have included, for example, central processing unit board, a read only memory board for storing the operational programs, a high speed RAM memory board, additional logic circuit boards, and a dedicated board per device to be interfaced to the line. A typical example is the unit illustrated in FIG. 1. A plurality of printed circuit boards 10 are contained in a board cage interconnected to a printed circuit back plane board 12 through the edge connectors of the individual pluged-in circuit boards. A plurality of input/output connectors 14 are mounted to the rear panel 16 and are connected by ribbon cables 18 to connectors 20 on the front of the printed circuit boards 10. The power supply 22 in the rear of the unit is connected to the back plane printed circuit board 12 by connector and line 24. The front panel 26 includes a plurality of switches 28 and indicators 30 mounted thereon and interconnected to the back plane printed circuit board by ribbon cable 32. A fan 34 is provided in the rear of the unit to cool the commonly housed power supply and printed circuit board elements. The communication interface adaptor of FIG. 1, by providing a plurality of printed circuit boards having individual electronic systems thereon, is readily adaptable to interface with any type of peripheral to any type of communication line. The trade-off for the universality is the increased size of the unit.
Communication interface adaptors dedicated to a specific peripheral interfacing with a specific line have been made using a single printed circuit board. As illustrated in FIG. 2, the single board 40 is mechanically mounted perpendicular to a face plate 42 and electrically interconnected thereto. A plurality of switches 44 and indicators 46 are contained on the face plate 42. The printed circuit 40 is interconnected electrically to the system it is dedicated to by edge connectors on the rear of the board. As can be seen, the single card communication interface adaptor follows the same development philosophy of the multiple board adaptor wherein the printed circuit boards are mounted perpendicular to the front panel, which includes the indicators and switches mounted thereon. The printed circuit board must be electrically interconnected to the front panel and is connected to the power supply and input terminals through additional connectors and cable which are attached to the rear edge connectors of the printed circuit board.
The interconnection of the printed circuit board to the front panel and the power supply through connectors and cables increases the expense in fabrication in parts as well as labor. Similarily, by mounting the printed circuit board perpendicular to the front panel, the total unit housing doesn't make efficient use of the interior space. Similarily, by providing the power supply within the same housing as the printed circuit board or boards, the overall size of the housing is increased and the boards are subjected to increased temperatures which shortens the life of the components and affects their operating characteristics. Thus, there exists a need for a new design for an interface adaptor printed circuit board and housing.